基于LaNi_(0.6)Fe_(0.4)O_(3–δ)致密扩散障型极限电流氧传感器的制备及性能

Preparation and Properties of Amperometric Oxygen Sensor Based on Dense Diffusion Barrier with LaNi_(0.6)Fe_(0.4)O_(3–δ)

采用溶胶–凝胶法制备LaNi_(0.6)Fe_(0.4)O_(3–δ)(LNF)和Ce_(0.9)Gd_(0.1)O_(1.95)(GDC)粉体,用X射线衍射仪对LNF粉体进行表征,利用扫描电子显微镜对LNF和GDC陶瓷片的断面形貌进行分析。以LNF为致密扩散障、GDC为固体电解质,用Pt浆黏合法制备致密扩散障型极限电流氧传感器,研究了氧含量和温度对氧传感器氧敏性能的影响。结果表明:LNF形成钙钛矿结构,LNF和GDC陶瓷片都烧结致密,无明显气孔;氧传感器在740~820℃温度范围内低氧含量(0.3%~1.1%)中显示出良好的极限电流平台;氧传感器响应时间和恢复时间较短,分别约为18和23 s,并且极限电流值与氧浓度φ(O_2)和温度(T^(–0.5))之间存在较好的线性关系。

The powders of LaNi（0.6）Fe（0.4）O（3–δ）（LNF） and Ce（0.9）Gd（0.1）O（1.95）（GDC） were prepared via a sol–gel method. LNF powder was characterized by X-ray diffraction（XRD）. The morphology of the piece sections of LNF and GDC ceramics was determined by scanning electron microscopy. A limiting current oxygen sensor using GDC as a solid electrolyte layer and LNF mixed ion-electron conductor as a dense diffusion barrier was developed via a Pt liquid agglutination method. The influences of temperature and oxygen content on the oxygen sensitive characteristic for oxygen sensor were investigated. Based on the XRD result, LNF powder has a single perovskite structure. LNF and GDC ceramic both have a greater sintered density and a lower porosity. The sensor has a good stable current plateaus at 740–820 ℃ as the oxygen concentration increases from 0.3% to 1.1%. Besides, the response/recovery time of oxygen sensor are 18 and 23 s, respectively, showing the good response characteristics. Also, the limiting current is linearly related to the oxygen concentration and the temperature （T^（–0.5））.